2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/185113The road towards unification of elementary interactions is thought to start on the solid ground of a universal local gauge principle. I discuss the different types of bosonic gauge symmetries in gravitational and nongravitational (standard model) interactions and their extensions both fermionic, bosonic and with respect to space-time dimensions. The apparently paradoxical size and nature of the cosmological constant is sketched, which at first sight does not readily yield a clue as to the envelopping symmetry structure of a unified theory. Nevertheless a tentative outlook is given encouraging to proceed on this road.29 pages, 4 figuresHigh Energy Physics - Phenomenologytext